The hypothalamus regulates reproductive function, both in the male and female, by synthesizing and secreting luteinizing hormone releasing hormone. However, little is known about the neural mechanisms responsible for the control of this hormone synthesis and secretion. The studies outlined in this proposal are designed to study these neural mechanisms using a variety of pharmacological and biochmeical techniques. The incorporation of labeled amino acids into putative prohormones and hypothalamic peptides will be quantitated by high performance liquid chromatography (HPLC) using molecular exclusion and reverse phase columns. Incorporation both in vitro and in vivo will be examined . The kinetics of the in vivo biosynthesis of LHRH will be studied in the intact and castrated rat. We hope to establish the biosynthetic mechanism for LHRH and whether the rate of biosynthesis is altered under various pathological states. Using two in vitro incubation systems we will also investigate the neural control of LHRH synthesis and secretion. Hypothalamic peptides will be measured by radioimmunoassay while catecholamines and indolamines will be monitored by electrochemical detection. A variety of kinetic and pharmacological experiments are planned to investigate the role of biogenic amines and cyclic AMP in LHRH release and synthesis.